[1] Solids of the approximate formula As2S5 have been used as pigments and chemical intermediates but are generally only of interest in academic laboratories.

[2] Arsenic pentasulfide is prepared by precipitation from an acidic solution of soluble As(V) salts by treatment with hydrogen sulfide.

[3] It may be also prepared by heating a mixture of arsenic and sulfur, extracting the fused mass with an ammonia solution and reprecipitating arsenic pentasulfide at low temperature by addition of hydrochloric acid.

Arsenic pentasulfide hydrolyzes in boiling water, giving arsenous acid and sulfur: It oxidizes in air at elevated temperatures producing arsenic oxides, the products and yields of which are variable.

In alkali metal sulfide solutions arsenic pentasulfide forms a thioarsenate anion, [AsS4]3−, which contain As(V) centres.